Cushioning device for hoist chains



May 9, 1967 H. v. HAWKINS ET AL 3,318,575

CUSHIONING DEVICE FOR HOIST CHAINS Filed May 18, 1965 S Sheets-Sheet 1 mar.

4 l y wig @mllidm .16 2M '6 I I I I I 3o II L h 32 M W lam H' 2a INVENTORS I HAROLD v. HAWKINS BY AND 22 h RALPH A. DICK A TTORNE Y5 May 9, 1967 H. v. HAWKINS E AL 3,318,575

CUSHIONING DEVICE FOR HOIST CHAINS Filed May 18, 1965 s Sheets-Sheet 2 INVENTORS HAROLD V. HAWKINS AND BY RALPH A. DICK A T TOR/VFYS May 9, 1967 H. v. HAWKINS ET L 3,318,575

CUSHIONING DEVICE FOR HOIST CHAINS 7 Filed May 18,, 1965 3 Sheets-Sheet 3 Ii-mill... I

INVENTORS HAROLD V. HAWKNS RALPH A. DICK 644w, GM

ATTORNEYS United States Patent 3 318,575 CUSHIONING DEVICE FOR HOIST CHAINS Harold V. Hawkins, 4895 Meadowbrook Road, Clarence 14031, and Ralph A. Dick, 4148 Fireside Drive, Williamsville, N.Y. 14221 Filed May 18, 1965, Ser. No. 456,780 1 Claim. (Cl. 254-167) This invention relates to chain hoists, and more particularly to improvements therein whereby the mechanism is protected from damaging shock stresses whenever the load lift chain is inadvertently driven to run-out at appreciable speed in either direction against its limits, whereby either the lift hook block or the dead-end of the lift chain is accidentally brought into collision with the main hoist frame. to provide in a chain hoist an improved shock cushion device for the aforesaid purposes.

Another object of the invention is to provide in a hoist as aforesaid an improved load lift hook block embodying a structurally simple but functionally improved cushion device, for use in connection with chain hoists of various types.

Another object is to provide in a hoist as aforesaid an improved shock absorber device in conjunction with the dead-end portion of the hoist load lift chain.

Other objects and advantages of the invention will be apparent from the specification hereinafter, and the accompanying drawing wherein:

FIG. 1 is a vertical sectional view through a chain hoist load lift block equipped with a cushion device of the invention;

FIG. 2 is a fragmentary vertical section corresponding to FIG. 1 but of another form of block of the invention;

FIG. 3 is a fragmentary sectional view showing a cushion device of the invention embodied in the main hoist frame;

FIG. 4 is a fragmentary parti-elevational-sectional view corresponding to FIG. 1 but showing still another form of load block cushion device;

FIG. 5 is a section taken as suggested by line 55 of FIG. 1;

FIG. 6 is a side elevational view showing still another from of load lift block and cushion arrangement of the invention; and

FIG. 7 is a side elevtaional view of a chain hoist embodying a lift chain dead-end cushion device as well as a load lift block cushion device of the present invention.

In the drawing herewith the invention is illustrated by way of example in conjunction with a typical type chain hoist, the main body of which is designated generally at 8 (FIG. 7). The load lift chain is designated generally at 10; the hook block is designated 12, and is shown as carrying a load lift book 14. As shown in FIGS. 1-6, the block 12 comprises essentially a cylindrically shaped casing 16 having a drilled or punched bottom wall 18 to receive in slip-fitting relation therethrough the shank 20 of the hook 14. A wear-resistant washer 22 and a bearing block 24 are preferably disposed as shown under the hook holding nut 26, which is threaded upon the upper end of the hook shank and locked thereon as by means of a cotter pin 28. At its upper end the casing 16 is closed by a plug 30 which is held in place by a cross-pin 32; the plug 30 being vertically slotted as shown at 34 to accommodate the lowermost link of the chain 10 which engages upon the pin 32. Thus, the hook block 12 is readily assembled to the load chain 10 by simply driving the pin 32 in place, and the hook 14 is thereby connected in freely swivelable relation in the hook block 12 and relative to the load chain 10.

In accordance with the present invention, as shown by way of example in FIG. 1 of the drawing herewith, a

Thus, an object of the present invention is 3,318,575 Patented May 9, 1967 shock cushion device may be provided in the form of an annulus 40 fabricated of a flexible energy absorbing type material such as for example a urethane elastomer or rubber like material which offers toughness and durability. The annulus 40 is dimensioned to slip-fit over the chain 10 and to rest upon the upper end of the hook block 12. A bearing washer as indicated at 42 is centrally apertured as indicated at FIG. 5 so as to also slip-fit downwardly over the chain 10 and in bearing relation against the top end of the annulus 40. Thus, it will be seen that as shown in FIG. 1, whenever the hook block is accidentally run up into collision with the main hoist frame 44 (FIGS. 1-3) the shock stresses of the collision will be absorbed by the annulus 40. FIG. 2 illustrates another form of the invention wherein the shock member 40 is retained in place and armored against impact damage by means of a yoke member 46 having its top plate portion apertured as shown in FIG. 5 and bearing downwardly upon the top end of the shock pad 40. The opposite legs of the yoke member 40 are provided with vertically elongate apertures as indicated at 48 to engage about the opposite end portions of the book block pin 32, which in this case is extended at both ends somewhat beyond the outer diameter of the casing 16.

FIG. 3 illustrates another form of shock block arrangement, wherein an annulus 50 of energy absorbing material as aforesaid is cemented or otherwise attached to the under surface of the main hoist frame 44, to receive the collision stresses whenever the hook block 16 is accidentally driven too high. FIG. 4 illustrates use of a cushion block 52 without the addition of any bearing plate or the like; it being understood that the block 52 is centrally apertured as in the manner of the bearing plate 42, as shown best in FIG. 5, to maintain the shock pad 52 in suitably anchored relation on the chain.

FIG. 6 illustrates another form of the invention wherein a plurality of shock pads, in this case a pair of pads designated 54, 56, made of material as aforesaid are mounted upon the upper "end of the hook block 12. A hearing washer 53 is disposed between the pads 54, 56, and atop bearing plate 60 is disposed to rest upon the uppermost pad; it being understood that the energy absorbing pads and bearing plates in all cases are preferably apertured in accordance with the pattern shown in FIG. 5 so as to provide for automatic stabilization of the shock device components in operational position, thereby minimizing Wear and tear thereon. It is a particular feature of the arrangement of FIG. 6 for example that by reason of providing a plurality of relatively short shock pads (54, 56) instead of a single pad of a height equaling the combined heights of the pads 54, 56, a much more rugged and durable shock absorbing unit is provided. This is because the multiple pads of lesser heights are subjected to much lower internal structural deflections, than would be experienced by portions of a single shock pad of greater height.

Hence, a construction of the type of FIG. 6 provides not only the same energy-absorbing capabilities as in the case of a single pad of the same total height but performs in improved manner and is more durable than other type devices. As stated, the pads 54, 56, as well as the washer 58 and the bearing plate 60 will all be preferably apertured as illustrated for example in FIG. 5. Hence, all of the components of the shock absorber unit are individually held against rotation relative to the load chain and the load block, whereby wearing frictions on the parts are avoided such as would otherwise tend to cause relatively rapid wear and/or disintegration of the energy absorbing components. It will of course be understood that whereas only two cushion pads are illustrated as being employed in FIG. 6, any other preferred number of pads may be employed in combination with corresponding bearing plates, in order to attain any preferred structural and/ or operational characteristics and capabilities.

' FIG. 7 illustrates application of the invention both to the load lift hook block and to the dead-end of the load lift chain. As shown therein, the dead-end portion of the load lift chain is designated at 62, and is deadended or fixed to the hoist frame as indicated at 64. In the event the load is lowered to the lowermost limit of the length of the load chain the looped slack portion of the chain as indicated at 62 is taken up, and if the lowering operation is not stopped in time, the hoist mechanism jams due to the sudden running out of slack chain. To shield the hoist mechanism against such damaging shock stresses in the case of the present invention, a shock absorber as indicated at 66 is included in the slack portion of theload chain just ahead of the dead-end connection 64. This shock absorber may be essentially of the type illustrated in FIGS. 1-6 referred to hereinabove. Hence, as shown in FIG. 7, this will include in any event a generally cylindrical shaped body carrying a crosspin 68 which engages a chain link 69 disposed interiorly of the casing 66; the opposite ends of the chain link 69 being in turn engaged by contiguous links'of the load chain. A shock block 70 centrally apertured to slide-fit into operative position on the chain as shown and so as to be non-rotative relative to the chain, is provided to project from theend of the cylinder 66. Hence, the pad 70 is thereby adapted to first come into abutting engagement with the hoist frame whenever the load chain is lowered so as to bring the shock absorber into reach of the hoist frame; thereby providing the shock protective features referred to hereinabove. 7

Thus, although only a few forms'of the invention have been illustrated and described in detail hereinabove, it will be understood that various changes may be made therein without departing from the spirit of the invention or the scope of the following claim.

4. We claim: In a chain hoist system comprising a main hoist frame, a load lift chain training therethrough and having at one end thereof a load lift block and being slack-looped at its other end into dead-end connection with said frame,

the improvement comprising a cushion device for dampen ing the shock stresses on said system caused by accidental running-out of said chain slack loop, said cushion device comprising-a cushion formed of energy absorbing material apertured to accommodate said chain in non-rotative relation therethrough and disposed thereon to encircle said chain ahead of the dead-end'connection therevof and being so dimensioned and securely positioned on the chain as to collide with said frame prior to tautening of the chain slack-looped portion, a second cushion device interposed between said frame and said load lift block for dampening the shock stresses on said system caused by accidental collision of said load lift block againstsaid frame, said cushion-devices comprise a cylindrical body have a transverse opening, a cross-pin received in said 7 opening and projecting through one of the links of said.

chain, and a cushioned block encircling said chain and set against one end face of said cylindrical body.

References Cited by the Examiner UNITED STATES PATENTS EVON BLUNK, Primary Examiner.

H. C. HORNSBY, Assistant Examiner. 

